Since a solution type polyurethane adhesive has excellent flexibility and excellent resistance to a plasticizer, it has hitherto been used as an all-round adhesive in various fields for adhering shaped products (e.g sheet and film) made from polyvinyl chloride which contain a large amount of a plasticizer with other plastic substances, wooden products or metallic products. However, it has still been desired to develop an improved adhesive having excellent heat resistance and improved performance and being capable of preventing lowering of adhesion which is induced by migration of the plasticizer from the substance to be adhered to the interface thereof. Moreover, the solvent solution type adhesive comprising a urethane rubber has less tack strength, and hence, for effecting the required adhesion, it is required to take such steps as applying the adhesive to both surfaces of the substances to be adhered, after taking some open time for drying the solvent, piling both surfaces against each other, pressing the piled substances, and further tacking temporarily by some means until adhesion by the adhesive is completed